The administration of medicinal products into the circulatory system of the human body is carried out either by the venous route or by the arterial route.
To administer these medicinal products, a catheter has to be placed, which consists of a tube having a smaller diameter than that of the venous or arterial vessels. Such catheters can be useful not only for the injection of medicinal products, but also to sense blood pressures in the venous system or in the arterial system.
In general, one distinguishes between two types of catheters: catheters for the peripheral venous routes and catheters for the central venous or arterial routes.
The peripheral venous catheters are placed at the level of a peripheral vein, that is, usually, at the level of the upper limbs of the patient, where the vein in question can be a vein of the forearm or a vein of the bend of the elbow. Among these catheters, there is the relatively short single venous catheter, having a length of approximately 5-6 cm, which is placed in a peripheral vein and whose part exiting from the vein is fixed to the skin of the patient using simple adhesives, to administer products or solutions over several hours, that is, over a relatively limited time period. The site of the puncture can be changed repeatedly as a function of the resistance of the peripheral veins.
The central venous catheter or the central arterial catheter is placed into deep venous trunks, that is into the large veins. Usually this means the internal or external jugular vein, the subclavian vein or the femoral vein.
The placement of these catheters is carried out by the cutaneous route, that is into the skin and in the location of the vein in which one wishes to place the catheter. For this, a cutaneous puncture is made into the vein through the intermediary of a rigid trocar, which is a kind of guide, fitted with a syringe at the end opposite the part which is introduced into the vein, allowing aspiration of the venous blood. Once this trocar is positioned in the venous trunk, the catheter is introduced after withdrawal of the syringe to allow the placement of this catheter in the vein of larger diameter.
As far as the central venous catheter or the central arterial catheter is concerned, it is connected at the end opposite the part which is introduced into the large vein, that is, immediately at the place where it comes out of the skin, to a support, generally a rigid plastic material, which constitutes a connection part which links this catheter to one or more catheters or external tubes, whose number can range up to five, and in which several different products circulate, which can be administered simultaneously, and which arrive in the support, which is in the form of a housing, and are then introduced into the catheter placed in the large vein. Usually, this support has a general triangular, sometimes circular, shape, and it is equipped with two external wings which allow the support to be fixed to the skin of the patient through the intermediary of a suture thread.
However, these different means of fixing catheters to the skin have the major drawback of being the sites of infections at the level of the puncture and penetration of the venous or arterial catheter, and, consequently, daily dressings have to be applied to prevent such infections, which may cause septicemia. In addition, when these dressings are placed at the femoral or jugular level, they create a real obstacle in the anatomical area, reducing the mobility and generating difficulties for the patient who wears a central venous catheter.
In addition, as already mentioned above, the catheters for the central venous routes have the drawback of using suture threads for fixing the support of this catheter, to which external catheters lead, with the associated risk for the operators, namely the intensive care personnel and the nurses.
Moreover, the administration of chemotherapy products is carried out using the central venous route, that is by placing a catheter in a large vein, and this catheter is connected to an injection chamber which is implanted under the skin generally at the level of the right or left pectoral muscle of the patient. Access is gained using the internal jugular artery, and the subcutaneous chamber is punctured using a Huber needle bent at a right angle and left in place as long as required for the chemotherapy product to be administered by perfusion under good conditions. The placement of this needle requires that it be maintained under the skin using adhesive means, which are not only unsuitable, but can sometimes result in infections at the sites of the cutaneous punctures as well. Consequently, dressings and compresses have to be used for protection to prevent any infection and allow the chemotherapy to be administered.